Escapement for card or tape reader

ABSTRACT

In a card or tape reader of the type in which a ratchet wheel (escapement wheel) is imparted with a continuous torque and its rotation is controlled by controlling a stopper which engages with the teeth of the ratchet (escapement) wheel thereby intermittently feeding a paper tape or card, an electrical circuit arrangement for extending the control time of the stopper and more particularly a stopper control time extension circuit in parallel with a conventional control circuit. When a code or signal indicates that the reader is not required to be stopped, stopper holding current is supplied to a magnet which attracts the stopper. The feeding speed may be remarkably increased.

United States Patent Inventors Appl. No. Filed Patented AssigneePriority ESCAPEMENT FOR CARD 0R TAPE READER 2 Claims, 4 Drawing Figs.

US. Cl 226/24, 226/76, 226/120 IIILCI ..Gllb 15/24 Field of Search [56]References Cited UNITED STATES PATENTS 1,023,797 4/1912 Batdorf 226/76 X3,181,759 5/1965 Maples 226/76 X 3,460,732 8/ I969 Kallenberg 226/157 XPrimary Examiner-Allen N. Knowles Attorney-Burgess, Ryan & HicksABSTRACT: In a card or tape reader of the type in which a ratchet wheel(escapement wheel) is imparted with a continuous torque and its rotationis controlled by controlling a stopper which engages with the teeth ofthe ratchet (escapement) wheel thereby intermittently feeding a papertape or card, an electrical circuit arrangement for extending thecontrol time of the stopper and more particularly a stopper c0ntrol timeextension circuit in parallel with a conventional control circuit. Whena code or signal indicates that the reader is not required to bestopped, stopper holding current is supplied to a magnet which attractsthe stopper. The feeding speed may be remarkably increased.

PATENTEDUBT 51971 3510495 sum 1 or 2 ESCAPEMENT FOR CARD OR TAPE READERBACKGROUND OF THE INVENTION The present invention relates to a card ortape reader such as a punched card or tape reader and more particularlyto an escapement used in the reader.

In the reader of the type described above, an escapement is utilized asa card or tape feed mechanism. Essentially the escapement is such that aratchet (escapement) wheel is imparted with a force so as to rotatecontinuously and a stopper pawl or pallet which engages with the teethof the ratchet (escapement) wheel is so regulated as to intermittentlyimpart the torque of the ratchet (escapement) wheel to a driven shaft.In a conventional paper tape or card reader, a sprocket wheel or pinchroller is carried by a driven shaft which also carried a ratchet wheelthrough a friction disk and a stopper which engages with the ratchetwheel is controlled by a magnet or the like whereby the paper tape orthe card is advanced and stopped for each code or character.

In operation of the magnet, the response or rise time and releasing timeare involved. The maximum speed available when the escapement is used islimited by the following relation:

Magnet releasing time+marginal time=time for escaping one tooth of theratchet wheel and arresting the next tooth. Therefore, the time forfeeding one character requires response or rise time=releasingtime=marginal time.

In the conventional reader, therefore, the intermittent movement speedof the driven shaft cannot be increased to the speed of the drive shafthowever well the characteristics of the magnet may be improved orwhatever higher the speed of the drive shaft may be increased as far asthe intermittent movement for each character is carried out.

In view of the above, the primary object of the present invention is toincrease remarkably the tape or card feed speed by rotating the drivenshaft substantially at the same speed with that of the drive shaft whenrequired, thereby eliminating the defects or disadvantages encounteredin the prior art.

SUMMARY OF THE INVENTION According to the present invention, in a cardor tape reader of the type in which a ratchet wheel is always impartedwith a force so as to rotate continuously and its rotation is controlledby controlling a stopper which engages with the teeth of the ratchetwheel, thereby intermittently feeding the paper tape or the card, anescapement is provided which comprises means for extending the stoppercontrol time thereby clearing the stopper from the teeth of the ratchetwheel and in which the stopper-holding current is supplied to a magnetwhich attracts the stopper when a signal or code represents that thereader is not required to be stopped.

According to the present invention, as means for extending the stoppercontrol time there is provided a stopper control time extension circuitin parallel with a conventional magnet control circuit so that thestopper may remain attracted by the magnet for a time longer than theordinary stopper-attracting time, thereby permitting the continuous feedof the paper tape or card. According to one embodiment of the presentinvention, the above-described stopper control time extension circuitcomprises of a flip-flop and a Darlington circuit connected in series.

The above and other objects, features and advantages of the presentinvention will become more apparent from the following description ofone example of the prior art and one illustrative embodiment of thepresent invention with reference to the accompanying drawing.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a perspective view of anescapement utilized in the prior art and in the present invention;

FIG. 2 is one embodiment of a control circuit according to the presentinvention;

FIG. 3 is a time chart ofa conventional escapement; and

FIG. 4 is a time chart of the escapement of the present in vention.

DESCRIPTION OF THE PREFERRED EMBODIMENT FIG. 1 illustrates aphotoelectric-type reader provided with a conventional escapement whichis utilized in the present invention. Reference numeral 1 designates amain drive shaft directly connected to an electric motor and driven inthe direction indicated by the arrow; 2, a locknut which presses afriction disk 5 against a ratchet wheel 6 through a friction spring 4and a washer 3; 7, a driven shaft directly connected to the ratchetwheel 6; and 8, a sprocket wheel directly coupled to the driven shaft 7and provided with sprocket pins or teeth 9 for feeding a card or tape. Atape 10 is provided with feed holes or perforations l1 and punched holes12 indicating various codes which may be read out optically by aphotoelectric element 13 in a manner well known in the art. An armaturestopper 14 is adapted to engage with the ratchet wheel 6 and when thearmature stopper 14 is attracted by a magnet 15, the stopper 14 isdisengaged from the teeth of the ratchet wheel 6 so that the drivenshaft 7 is rotated. Upon deenergization of the magnet 15, the armaturestopper I4 is returned to its normal position by a return spring 16 sothat the stopper I4 engages with the teeth of the ratchet wheel 6,thereby stopping the rotation thereof and consequently the driven shaft.Reference numeral 17 designates lead wires to a coil of the magnet 15.

FIG. 2 illustrates one embodiment of a control circuit for energizingthe magnet 15 of the escapement described above according to the presentinvention. Reference numerals 20, 21 and 22 designate control terminals;23, a monostable mul' tivibrator to be energized by a signal from thecontact 20; 25. a flip-flop which is set by signal from the terminal 21and is reset by a signal from the terminal 22; 24 and 26, Darlingtoncircuits which energize the magnet 15 when the monostable multivibrator23 or the flip-flop 25 is actuated; R and R. are resistor connected inseries to the magnet 15. In this case, R R,.

FIG. 3 illustrates a time chart of the intermittent movement by theconventional escapement mechanism while FIG. 4, the time chart of thepresent invention which permits the continuous feed movement if desired.1,, (where n=l ,2 8) designates time. 31 designates the feed hole outputobtained by reading the feed holes 11 of the tape 10 shown in FIG. 1.Feed holes produce high level outputs while no feed hole produces thelow-level output. 32 designates the reading gate signals which representthe time to read out the punched holes 12. When the reading gate signalis at its high level, the punched holes or codes are read out while whenthe reading signal is at its low level the magnet 15 is controlled. 33designates the waveform of the output of the monostable multivibrator 23which is energized if required when the gate signal is at its low level.34 designates the waveform of the current passing through the coil ofthe magnet 15. 35 in FIG. 4 designates the waveform of the output of theflip-flop 25.

With reference to FIG. 3, the intermittent movement for each code of theconventional escapement will be described. When the read" instruction isgiven to the tape reader which is not actuated, the reader gate will beopened for t as indicated by the waveform 32. When the signal of thereader gate is at its low level and when the conditions for continuousoperation are not given, the output of the monostable multivibrator 23in FIG. 2 rises for 1 as indicated by the waveform 33 in FIG. 3, so thatthe magnet 15 is energized through the Darlington circuit 24. In thiscase, the current flows through the coil of the magnet 15 as indicatedby the waveform 34 in FIG. 3. When the armature stopper 14 is attractedby the magnet 15 so that the tape 10 is transported, the positions ofthe feed holes 11 are displaced (the displacement starts from thestepped portion of the waveform 34), the feed hole output rises to itshigh level as indicated by the waveform 31 after 1 and then after t, thefeed hole output falls down to the low level and the next code orp'unched holes is read out. After t the magnet is deenergized, but thereleasing time lags for time t by a surge suppressor which is normallyprovided, due to the so-called sticking." However, the armature stopperis released sufficiently before the next tooth of the ratchet wheelpasses away, that is within the time 5,. Thus, the reader is returned toits initial condition similar to that before the read instruction wasreceived.

Next the present invention which permits the continuous operation willbe described with reference to FIG. 4. The magnet 15 is energized by therea instruction as described with reference to FIG. 3 and a series ofoperation steps are cycled. When-it is not required to stop the papertape or card after the reader having read out one code during the time tduring which the reader gate is opened, (for example, in case of theinvalid codes or fast-forward codes), the flip-flop 25 in FIG. 2 is setso that the magnet 15 is kept energized continuously through theDarlington circuit 26. Therefore, even when the output of the monostablemultivibrator 23 reaches the low level as indicated by the waveform 33,the magnet 15 remains energized by the output of the flip-flop 25 asindicated by the waveform 33. In this case, since the magnet 15 may bekept energized by the holding current which is less than the currentrequired for energizing the magnet, the current is fed through theresistor R whose resistance is far higher than that of the resistor RThus, the magnet 15 is kept energized by a relatively small currentafter t, as indicated by the waveform 34.

Now the paper tape may be fed at a speed corresponding to the rpm. ofthe motor. When the signal representing the Stop instruction is readout, the Stop" instruction is given by the falling or dropping trailingedge of the reader gate pulse L, so that the signal from the resetterminal 22 shown in FIG, 2 resets the flip-flop 25, thereby stoppingthe holding current to the magnet 15. Thus, the stopper 14 engages withthe teeth of the ratchet wheel 6, thereby stopping the tape. in thiscase, the current is low as shown by the waveform 34 in FIG. 4,

sticking time of the magnet 15 is very shorter as compared with theabove-described sticking" time 1 so that the magnet is released in astable manner within the next time t Thus, it will be understood thatthe paper tape or the card may be advanced for each code and may beadvanced continuously when desired by extending the time for attractingthe stopper, so that the readout may be carried out efficiently at themaximum speed.

We claim:

I. In an intermittent movement device for intermittently feeding a papertape or card of the type in which a ratchet wheel is imparted with acontinuous rotational force and the rotation of said ratchet wheel iscontrolled by controlling a stopper which engages with the teeth of saidratchet wheel, the improvement comprising an escapement having means forextending the control time of said stopper including a series circuitconsisting of a flip-flop and a Darlington circuit, which series circuitis connected in parallel to a stopper control circuit.

2. In an intermittent movement device for intermittently feeding a papertape or card of the type in which a ratchet wheel is imparted with acontinuous rotational force and the rotation of said ratchet wheel iscontrolled by controlling a stopper which engages with the teeth of saidratchet wheel, a magnet is adapted to be energized to attract andmaintain said stopper out of engagement with said ratchet wheel, andsaid tape or card includes openings producing high level output whenexposed to reading means, the improvement comprising said tape or cardhaving a predetermined length absent of openings to produce a low-leveloutput when exposed to said reading means; and

circuit means electrically connected with said magnet and responsive tosaid low-level output, to energize said magnet and hold said stopper inattracted position when said tape or card is rcad out on saidpredetermined length.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3 495Dated October 5, 1971 Invent I-( Noboru Murayama, et a1.

It is certified that error appears in the above-identified patent andthat said Letters Patent are hereby corrected as shown below:

Column 1, line 28, change to (both instances) Column 2, line 39, change"resistor" to resistors Signed and sealed this 16th day of May 1972.

( SEAL Attsst":

EDWARD I LFLETCHER JR R0 BERT GO'I'TSC HALK Attesting Officer-Commissioner of Patents FORM Po-wso (1069l 1770-149 USCOMM-DC 60376-P69e u.s. uovsnmasm nznn'me OFFICE: mu 0-s5s-su

1. In an intermittent movement device for intermittently feeding a papertape or card of the type in which a ratchet wheel is imparted with acontinuous rotational force and the rotation of said ratchet wheel iscontrolled by controlling a stopper which engages with the teeth of saidratchet wheel, the improvement comprising an escapement having means forextending the control time of said stopper including a series circuitconsisting of a flip-flop and a Darlington circuit, which series circuitis connected in parallel to a stopper control circuit.
 2. In anintermittent movement device for intermittently feeding a paper tape orcard of the type in which a ratchet wheel is imparted with a continuousrotational force and the rotation of said ratchet wheel is controlled bycontrolling a stopper which engages with the teeth of said ratchetwheel, a magnet is adapted to be energized to attract and maintain saidstopper out of engagement with said ratchet wheel, and said tape or cardincludes openings producing high level output when exposed to readingmeans, the improvement comprising said tape or card having apredetermined length absent of openings to produce a low-level outputwhen exposed to said reading means; and circuit means electricallyconnected with said magnet and responsive to said low-level output, toenergize said magnet and hold said stopper in attracted position whensaid tape or card is read out on said predetermined length.